As described above, the SEM or the AFM has been widely used to observe the microstructure of the sample. As described above, the SEM has an advantage that it may perform high-rate scan, and the AFM has an advantage that it may perform three-dimensional observation up to the level much more precise than that of the SEM. Therefore, research and development for combining two types of microscopes with each other have been conducted. As a part of this research, there is a Korean Patent Registration No. 1158284 (entitled “Composite Measuring Apparatus”) (hereinafter, referred to as “the related art”). In the related art, an atomic microscope measuring a surface of a sample substrate in an atomic level and a composite measuring apparatus of the atomic microscope and an electron microscope measuring the sample substrate have been disclosed. The composite measuring apparatus measures the surface of the sample substrate in an atomic level by the atomic microscope. However, unlike a general atomic force microscope, in the composite measuring apparatus, the sample is disposed perpendicularly to the ground, and a probe approaches the sample from a side surface. In addition, the composite measuring apparatus images a side surface of the atomic microscope and an end surface of the sample substrate by the electron microscope by allowing an electron beam to be incident to the surface of the sample substrate in parallel with the surface of the sample substrate. When the composite measuring apparatus is used, it is possible to observe an interaction between the probe of the atomic microscope and the surface of the sample substrate by the electron beam while observing the surface of the sample substrate by the atomic microscope. That is, when the composite measuring apparatus is used, a state in which the probe of the atomic microscope is worn or damaged may be monitored in real time by the electron microscope, and thus, a work for replacing the probe may be performed at a required time. Therefore, when it is observed that the probe is worn or damaged, a risk that an inaccurate result will be generated is removed in advance, thereby making it possible to improve accuracy and reliability of observation.
Meanwhile, unlike the related art, research for combining the advantage of the SEM that may perform the high-rate scan and the advantage of the AFM that may perform the precise observation with each other has been conducted. That is, it is possible to accurately and rapidly find a target position while observing the surface of the sample in real time by the SEM and perform more precise observation in the atomic image level by the AFM at the target position.
However, the following problems are present in realizing the combination of the SEM and the AFM as described above. As described above, an operation principle of the AFM is to allow the cantilever having the probe disposed at the tip thereof to approach a surface of an observation target object, measure a deformation degree of the cantilever by atomic force formed between the tip of the probe and the surface of the target object, and measure a shape of the surface of the target object on the basis of the deformation degree. When considering this operation principle, in the case in which noise such as external vibration is generated, undesired deformation of the cantilever is generated, such that there is a risk that reliability of an observation result will be decreased. However, since it is substantially difficult to completely exclude the generation of external vibration at the time of generation of mechanical movement, it is difficult to implement rapid movement of the AFM including the probe, and the like, for performing the high-rate scan.
Particularly, in the case of a beam bounce method of measuring movement of the probe using deflection of reflected light, which is most widely used among AFM atomic force measuring methods, separate components such as a plurality of mirrors, a position-sensitive photo-detector (PSPD), an optical fiber collimator, and the like, are required in addition to the cantilever including the probe, and these components should stably maintain fixed distances and positions with respect to the cantilever. However, in the case in which the external vibration that may not be disregarded is applied to the AFM as described above, distances and positions between the cantilever and these several other components may be finely changed, which may significantly decrease performance such as a resolution, a sensitivity, and the like, of the AFM and increase noise.
Furthermore, since several components should move together as described above, it is difficult to accurately adjust operations between actuators moving the respective components in the case of separately moving the respective components, the respective components may not rapidly move due to weights and volumes thereof in the structure according to the related art in the case of moving the respective components at a time, and the distances and the positions are easily changed or shaken in the case of rapidly moving the respective components, thereby causing bad dynamic characteristics such as large noise, or the like.